Support Zauth roles

[niknetniko]

This should work, but I don't have the bestuur role of course. We also still support the admin property of the user object, but not sure if that is still supported.

[hannes-dev]

Nice!
admin I think still works, but this only signifies if they are admin on Zauth, and not necessarily if they should be admin on other services (altough, of course, they can just give themselves any role)

Giving the bestuur admin is correct, but we've also been adding scoped roles for each service. I've made the zout_admin role for this and have given you this role, so you can test it with that!